Carburetor



June 3, 1941. R, EMERSON 2,244,519

CARBURETOR Filed Feb. 23; 1939 Patented June 3, 1941 iJETED STTES 'l' FF HQ CARBURETOR John RhEmerson, Flint, Mich, assignor to Borg- Warner Corporation, Chicago, 111., a corporation of Illinois 2 Claims.

ihis invention relates to carburetors and particularly to an improved arrangement of means for supplying an enrichening charge to the respective air passages of a multiple type of -carburetor when the throttles are moved in the opening direction.

Considerable difliculty has been experienced with known arrangements including overheating of the fuel in the relatively long passages connecting the accelerator pump with the enrichening nozzle; uneven delivery of enrichening fuel to the respective air passages; and other difficulties.

I have found that the above disadvantages are overcome and the operation of the carburetor materially improved by the provision of a single accelerator operated pump delivering through a single passage to a novel cluster jet arrangement. This single delivery passage extends from the pump to a point closely adjacent the position where it is desired to convert this single stream into a plurality of individual streams directed into the respective air passages. I have found that the heat of the engine has a decidedly reduced tendency to cause heating of the fuel in this single delivery passage and there is obtained a definitely improved distribution of enrichening fuel from my novel cluster jet.

The above and other objects, advantages and uses of my invention will become more apparent from a reading of the following specification and claims taken in connection with the appended drawing which forms a part of the specification and wherein:

Fig. 1 is a plan view taken on the line il of Fig. 2 showing a dual carburetor incorporating my invention;

Fig. 2 is a broken away elevation showing to advantage the relationship of interior structures;

Fig. 3 is an enlarged plan view in section taken substantially on the line 3-3 showing to advantage my novel cluster jet; and

Fig. 4. is an elevation taken on the line 'l4 of Fig. 3.

Indicated generally at ii] is a multiple type of carburetor incorporating a preferred embodiment of my invention and including an arrangement of lower generally parallel air passages H, in communication with a single upper passage Ha fuel bowl 1?, main nozzles I 3 for delivering fuel from the fuel bowl to the air passages, and throttle valves 35, one for each air passage, for controlling the flow therethrough. Both the throttles I5 are mounted on shaft i6 attached to the end of which is a linkage mechanism (not shown) for simultaneously operating the throttles. In addition to the above structure, the carburetor is provided with the usual additional equipment such as fuel inlet control valve ll, float l3, choke l9 and other conventional parts not essential to a disclosure of the present invention.

Enrichem'ng supply assembly In carburetors now in commercial use it is found necessary to inject an enrichening charge of fuel in the air stream when the throttles are opened, since at this time the sudden inrush of air would otherwise unduly lean out the mixture. It has been attempted heretofore to perform this function with various arrangements of structure. I propose the following improved arrangement including a cluster jet indicated generally at 2i) mounted on a recessed shoulder 2| in the rear central portion of the carburetor and communicating through a relatively short single passage 22 in the carburetor wall with the wall 23 of a single carburetor pump indicated generally at 24.

This cluster jet 25 is preferably composed of a body portion 33 centrally orificed at 35 and countersunk in the top portion thereof to provide chamber 32. Protuberant nozzle members 33 extend radially outwardly and downwardly and are so directed as to deliver an enrichening spray of fuel into the respective air passages H. Nozzle members 33 are formed with a fuel passage 39 therethrough restricted on the lower end as indicated at 34 to improve the form of spray and communicating at the upper end with countersunk chamber 32. A closure member indicated generally at 35 is provided for the nozzle body and includes the bonnet 36 engaging through a gasket 3?, the upper periphery of the body and having a downwardly depending stem 38 extending through the central orifice in the body member 30 and being in turn formed with a central passage partially therethrough merging in a cross-passage 40. Stem 38 is threaded on the lower portion thereof for attachment to a threaded opening in the shoulder 24, a second gasket 31 'being interposed between the body 30 and the shoulder 24. Member is additionally provided with a suitably shaped recess 4| therein for cooperation with a screw driver or other tool.

The radially oppositely extending protuberances 30a are for the purpose of locating the discharge nozzles and for preventing the turning of the nozzle cluster when the screw 35 is being tightened down.

The single accelerator pump 24 is of a wellknown type including plunger 50 connected with the pump actuating rod 5! through a spring lost motion connection 52, the pump rod being connected with the throttle linkage in a conventional manner (not shown) for operation thereby upon the opening of the throttles. The pump well 23 is supplied with fuel from the fuel bowl i 2 through the passage 53 and the one-way valve 54. The downward movement of the plunger 50 closes the one-way valve 5 8 and forces the fuel through the passage 22 and beyond the check valve 3453 and out through the nozzles 34. Because this structure is Well-known the details thereof are omitted for the purpose of simplicity.

Operation As the throttles are opened, pump rod 5| is simultaneously lowered thereby in a well-known manner (not shown) and the plunger 59 of pump 24 is subsequently urged downwardly by lost motion spring means 52, enriching fuel being forced out through the relatively short passage 22 up through passage 39 in the central portion of the cluster jet, cross-passage it where the same branches into two streams passing out through cluster jet nozzles 33 into the respective air passages Ii.

Since there is but one pump and one passage leading to a point adjacent the nozzle of the cluster jet, it is thus made possible to position the single delivery passage at a point removed from the hot engine side of the carburetor. I have shown this passage located centrally of the carburetor, however the same can be removed to the remote side of the carburetor from the engine if so desired to thus further improve the non-heating characteristics. By using a single passage and one pump leading to a point adjacent the multiple nozzles, I thus insure a more rapid movement of the fuel through this passage as well as a constant volume of fuel regardless of heat conditions.

By maintaining the fuel in a single stream and manifolding the same directly adjacent the discharge nozzle, I thus effect a more even distribution and equalized pressure of the fuel in the respective air passages.

While I have described my invention in connection with one specific embodiment thereof, this is by way of illustration and not by Way of limitation and I desire that the scope of my invention be defined solely by the appended claims which should be construed as broadly as the prior art will permit.

I claim:

1. In a multiple passage type of carburetor including means defining a single upper passage, means defining a plurality of individual lower passages in communication with said single passage, and means defining main fuel nozzles cooperating with said individual passages, the combination therewith of means defining a cluster jet for delivering separate streams of enriching fuel above each of said individual passages from a single supply passage in communication with said cluster jet, said cluster jet comprising a centrally orificed nozzle body terminating in the upper portion thereof in an enlarged chamber, outwardly and downwardly diverging protuberant nozzles formed on said body having passages therethrough communicating with said chamber, a closure member for said chamber comprising a head for engagement with the outer peripheral wall of said chamber and having a depending reduced stem portion extending through said central orifice and formed with a concentric passage extending partially therethrough and converging in a cross passage within said chamher, the lower end of said stem being threaded for connection with said single passage defining means.

2. In a down draft carburetor including means defining a housing having a single upper air inlet passage communicating with lower dual air and fuel mixture passages therebelow, a fuel bowl, main fuel nozzles for delivering fuel to each of said fuel passages from said fuel bowl, individual throttles for controlling the flow through each of said dual passages, and means in combination therewith for delivering enriching charges of fuel in the area above each of said dual passages in response to the opening of said throttles, said means comprising a pumping chamber formed in said housing at a position removed an appreciable distance internally away from the exterior heat exposed outer surface of said housing, said pumping chamber containing a piston operable in response to the opening of said throttles, a single relatively short fuel passage formed in said internal portion of said housing leading from said pump chamber to a position slightly above and generally between said dual passages and means defining a cluster jet in communication with said short single passage at the upper portion thereof, said cluster jet comprising one discharge nozzle for each of said dual passages arranged to discharge generally downwardly into the area at the upper inlet of said respective dual passages.

JOHN R. EMERSON. 

